My captions don’t update and don’t appear in my Table of Figures

When you add a caption to a floating graphic, by default Word puts the
caption in a textbox, which means it won't update and won't appear in the Table
of Figures.

To get round this you must make the graphic Inline, and then
insert the caption. If you need the graphic to behave like a floating object,
you then need to select the inline graphic and its caption simultaneously
and put them in a frame. For a fuller explanation of both the problem and the
workaround, see The draw layer: a metaphysical space.